Respiratory protective hoods are well known in the prior art They typically comprise an air-inpermeable enclosure sealed at the wearer's neck and fitted with a substantially transparent visor and breathing respirator.
Some respiratory protective hoods use a half-mask (aka "nose cup") breathing interface. The half-mask seals around the wearer's nose and mouth area. However, a half-mask must be sized to accommodate the facial variations within a given population and a particular sized half-mask must be matched to the proper user. The inability of a hood with a half-mask to universally fit an adult population significantly complicates the logistics of protecting that same population. Another drawback of a hood with half-mask is the size and cost. These masks are difficult to store in a compact form. This hinders the portability and storage properties of the mask. Hoods with a half-mask utilize a significant amount of materials, thereby increasing their costs. Still another drawback to these designs is the pressure needed to keep the half-mask sealed to the face. Methods of applying pressure include placing tensioned straps around the head of the wearer. Properly adjusting these straps requires additional training and expends additional donning time in an emergency situation. Furthermore, the tension used to draw the mask to the face makes the design highly claustrophobic. The greater sealing area and the required tensioning system necessitate higher manufacturing costs, greater weight, greater bulk and more complexity in operation.
Many problems with the hood with half-mask are overcome by the use of a mouthpiece respirator. Mouthpiece respirators engaged by the wearer's mouth purify air drawn in through the oral pathway to the lungs by inhalation. The mouthpiece respirators also provide a pathway for exhalation. The mouthpiece respirator provides a number of distinct advantages over a hood with half-mask.
Mouthpiece respirators may be engaged and disengaged by the wearer while still wearing the protective hood. In addition, tension straps are not required when using the mouthpiece respirator as the support and seal to the air purifying means is provided by the wearer's mouth. This provides a marked level of control and comfort by the wearer. Conversely, the wearer of a hood with half-mask suffers from continual pressure as the mask is pulled up against the face by tension in the straps.
An advantage of using a mouthpiece over a hood with half-mask is that of size. Mouthpiece respirators engage the oral cavity of the user while a half-mask must cover a significant area of the face. Accordingly, mouthpiece respirators are smaller and more compact while a hood with half-mask is larger and more bulky. This size difference also contributes to a lower manufacturing cost, better portability and easier storage for the mouthpiece design.
Another advantage of the mouthpiece respirator over a hood with half-mask is that of simplicity and speed. A hood with half-mask must be securely sealed against the face with a sufficient amount of pressure. If the amount of force is too little, leakage may occur, thereby lowering or negating the protection factor of the device. If the amount of force is too high, then the mask becomes too uncomfortable to wear. Some hoods with a half-mask utilize manual straps to adjust the tension level while other designs automatically provide a predetermined level of tension. Requiring the wearer to adjust manual straps in order to properly fit the hood requires significant training and repeated practice in order to assure the wearer is able to don the hood properly in an emergency situation. However, regardless of proficiency and skill, each adjustment step requires time in which the user may be subject to hazardous or even deadly conditions.
Designs that utilize a predetermined amount of tension to secure the mask risk being either uncomfortably tight or so loose that an effective seal is not obtained. It is important to note that an uncomfortable mask will likely be worn less than a comfortable mask. Tight-fitting masks may cause tissue soreness, claustrophobia, headaches and other ailments. A user suffering from these discomforts will not only become distracted from the tasks at hand, but will be more likely to remove the mask before it is safe to do so. Therefore, the comfort provided by the mouthpiece respirator has a direct and beneficial effect on the overall safety of the wearer and the ability of the wearer to maintain that safety level for extended periods of time. Nevertheless, a number of problems remain with current mouthpiece technology.
A significant problem with current mouthpiece designs is achieving and maintaining nasal occlusion. Protective hoods that utilize mouthpiece respirators will not function properly unless the nose is occluded. The wearer must not breath through his nose. Nasal inhalation effectively bypasses the purification systems connected to the mouthpiece respirator, which greatly diminishes the protection factor of the protective hood. In addition, continued nasal inhalation produces a vacuum within the hood enclosure. This vacuum may lead to the introduction of outside, contaminated air into the enclosure.
Without nasal occlusion, nasal exhalation bypasses the mouthpiece respirator. This may lead to the accumulation of moisture and carbon dioxide-rich air within the ocular region of the hood. The cumulative effect of this process may fog the hood's visor and cause the hood to become uncomfortably hot.
In order to achieve nasal occlusion, prior art protective hoods generally utilize a noseclip comprising two opposing nostril pads biased towards each other. The wearer places the noseclip over his nose which is then pinched off. Additionally, outward extending fingers may extend from each nostril pad permitting the wearer to engage or disengage the noseclip from his nose.
When utilizing a noseclip with current protective hoods, the noseclip must be engaged before the protective hood is donned. Once the noseclip is in place, the wearer may then don the protective hood over his head. However, once the protective hood is placed over the wearer's head, the noseclip may no longer be adjusted, repositioned, or put back on if it falls off without removing the hood or otherwise breaking the substantially airtight seal. This is a potentially dangerous situation for the wearer. If the wearer wishes to fix the noseclip to properly occlude the nose, he must break the airtight seal of the protective hood thereby exposing himself to hazardous conditions.
U.S. Pat. No. 5,186,165 to Swann describes a deployable hood and mouthpiece which utilize a flexible, substantially transparent hood in place of a visor. As the Swann patent utilizes a mouthpiece respirator, the requisite noseclip is also described and illustrated. While the flexible, substantially transparent hood in the Swann patent might permit limited external articulation of the noseclip; it does not provide a universal fit to an adult population. The noseclip in the Swann patent is pivotally secured to the mouthpiece (column 8, line 22). Accordingly, no adjustment means are taught or provided by the Swann patent. The flexible properties of the substantially transparent material in the Swann patent that permit limited external actuation of the noseclip also distort outward vision. There are no external grasping means for articulating the Swann noseclip. This would make external actuation a difficult and blind operation with no clear or obvious means of control, particularly in an emergency situation. Furthermore, materials and sealing mechanisms of the Swann patent do not provide for a substantially airtight seal required for chemical, biological and nuclear agent protection (column 9, lines 4-5). Consequently, what is needed is a means to externally actuate an integrated nose clip while providing a universal fit, clear outward vision, a substantially airtight seal, ease of use and little to no training to achieve proficiency.
With prolonged use, the wearer may wish to temporarily disengage or re-adjust the noseclip for comfort. Again, he must break the substantially airtight seal and expose himself to hazardous conditions to make the adjustments in the noseclip.
Another problem in the prior art involves the speed of donning the protective hood and establishing a secure respiratory pathway. With current designs, the wearer must first engage the noseclip before donning the protective hood. The action of putting on the noseclip is a critical element of use that requires proper training and practice. Furthermore, the step of engaging the noseclip must be done while the user is unprotected from hazardous conditions. It would be advantageous for the user to immediately don the protective hood and benefit from the hood's protection factor as soon as possible.
Still another problem in the prior art is that of multiple and separate parts. As the noseclip is separate from the protective hood there is a risk that the noseclip might be lost. As described above, the noseclip is a critical part to the proper use of a mouthpiece respirator. While noseclips have been tethered to protective hoods, they may still come apart from the attachment. It would be desirable to integrate the noseclip into the hood so that the possibility of losing a critical part is eliminated.
U.S. Pat. No. 1,978,994 to Fortunato (the '994 patent) describes a respiratory protective helmet having a forwardly extending cup-shaped nose piece enclosing a wire noseclip actuated externally to hold the nose closed and permit breathing only through the mouth. While nasal occlusion is externally actuated in the Fortunato patent, a number of drawbacks remain.
The nosepiece enclosure of the Fortunato patent significantly obstructs the view of the wearer. Maintaining clear outward vision is a highly desirable feature in respiratory protective hoods that often find use in military, law enforcement, and escape and rescue operations.
Another drawback with the Fortunato patent is that it does not accommodate facial variations between different users. There are no provisions for the wire noseclip to move laterally or longitudinally for a proper fit. If the noseclip is not positioned correctly to occlude the nose, the protection factor of the apparatus is significantly compromised.
Another drawback with the apparatus described in the Fortunato patent is that it does not pack into a compact size. Fortunato describes a helmet "preferably made from stiff rubber" (column 1, lines 42-43) and a "forwardly extending cup-shaped nose piece." (Column 2, lines 74-75). The ability of a respiratory protective device to fold into a compact design provides a number of important benefits including high portability and low storage requirements.
Consequently, there is a need in the art for an externally adjustable, integrated noseclip adapted for use with a respiratory protective hood that permits the user to immediately don the protective hood without requiring the user to first don and engage the nose clip.
There is a further need in the art for an externally adjustable, integrated noseclip that permits wearer to disengage and re-engage the noseclip without removing the protective hood or otherwise breaking the substantially airtight seal.
There is a further need in the art for an integrated noseclip that provides substantially unobstructed outward vision for the wearer.
There is a further need in the art for an integrated noseclip that can move in multiple directions to accommodate a wide variety of nose sizes, nose shapes and facial configurations.
There is a further need in the art for an integrated noseclip that can fold with a respiratory protective hood into a compact size for optimum storage and portability.
There is a further need in the art to reduce the number of separate parts needed to properly use a respiratory protective hood.
However, in view of the prior art at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.